Princeton's WordNet(5.00 / 1 vote)Rate this definition:

GCIDE(3.75 / 4 votes)Rate this definition:

Drug(n.)

any substance intended for use in the treatment, prevention, diagnosis, or cure of disease, especially one listed in the official pharmacopoeia published by a national authority.

Drug(n.)

any substance having psychological effects, such as a narcotic, stimulant, or hallucinogenic agent, especially habit-forming and addictive substances, sold or used illegally; as, a drug habit; a drug treatment program; a teenager into drugs; a drug bust; addicted to drugs; high on drugs.

Webster Dictionary(5.00 / 1 vote)Rate this definition:

any animal, vegetable, or mineral substance used in the composition of medicines; any stuff used in dyeing or in chemical operations

Drug(noun)

any commodity that lies on hand, or is not salable; an article of slow sale, or in no demand

Drug(verb)

to prescribe or administer drugs or medicines

Drug(verb)

to affect or season with drugs or ingredients; esp., to stupefy by a narcotic drug. Also Fig

Drug(verb)

to tincture with something offensive or injurious

Drug(verb)

to dose to excess with, or as with, drugs

Origin: [See 1st Drudge.]

Freebase(0.00 / 0 votes)Rate this definition:

Drug

A drug is a substance which may have medicinal, intoxicating, performance enhancing or other effects when taken or put into a human body or the body of another animal and is not considered a food or exclusively a food.
What is considered a drug rather than a food varies between cultures, and distinctions between drugs and foods and between kinds of drug are enshrined in laws which vary between jurisdictions and aim to restrict or prevent drug use. Even within a jurisdiction, however, the status of a substance may be uncertain or contested with respect to both whether it is a drug and how it should be classified if at all. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.
In pharmacology, a drug is "a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being." Drugs may be prescribed for a limited duration, or on a regular basis for chronic disorders.
Recreational drugs are chemical substances that affect the central nervous system, such as opioids or hallucinogens. They may be used for perceived beneficial effects on perception, consciousness, personality, and behavior. Some drugs can cause addiction and/or habituation.

Chambers 20th Century Dictionary(0.00 / 0 votes)Rate this definition:

Drug

drug, n. any substance used in the composition of medicine: an article that cannot be sold, generally owing to overproduction.—v.t. to mix or season with drugs: to dose to excess.—v.i. to prescribe drugs or medicines:—pr.p.drug′ging; pa.p. drugged.—n.Drug′gist, one who deals in drugs. [O. Fr. drogue, prob. from Dut. droog, dry; as if applied orig. to dried herbs.]